Delikanli Savas, Erdem Onur, Isik Furkan, Dehghanpour Baruj Hamed, Shabani Farzan, Yagci Huseyin Bilge, Durmusoglu Emek Goksu, Demir Hilmi Volkan
Department of Electrical and Electronics Engineering, Department of Physics, UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800, Turkey.
Luminous! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Materials Sciences, Nanyang Technological University, Singapore 639798, Singapore.
J Phys Chem Lett. 2021 Mar 11;12(9):2177-2182. doi: 10.1021/acs.jpclett.0c03836. Epub 2021 Feb 25.
We demonstrate amplified spontaneous emission (ASE) in solution with ultralow thresholds of 30 μJ/cm in red and of 44 μJ/cm in green from engineered colloidal quantum well (CQW) heterostructures. For this purpose, CdSe/CdS core/crown CQWs, designed to hit the green region, and CdSe/CdS@CdZnS core/crown@gradient-alloyed shell CQWs, further tuned to reach the red region by shell alloying, were employed to achieve high-performance ASE in the visible range. The net modal gain of these CQWs reaches 530 cm for the green and 201 cm for the red, 2-3 orders of magnitude larger than those of colloidal quantum dots (QDs) in solution. To explain the root cause for ultrahigh gain coefficient in solution, we show for the first time that the gain cross sections of these CQWs is ≥3.3 × 10 cm in the green and ≥1.3 × 10 cm in the red, which are two orders of magnitude larger compared to those of CQDs.
我们展示了在溶液中通过工程化胶体量子阱（CQW）异质结构实现的放大自发辐射（ASE），红色的超低阈值为30 μJ/cm²，绿色的超低阈值为44 μJ/cm²。为此，设计用于覆盖绿色区域的CdSe/CdS核/壳CQW，以及通过壳层合金化进一步调整以达到红色区域的CdSe/CdS@CdZnS核/壳@梯度合金化壳CQW，被用于在可见光范围内实现高性能ASE。这些CQW的净模态增益在绿色区域达到530 cm⁻¹，在红色区域达到201 cm⁻¹，比溶液中的胶体量子点（QD）大2 - 3个数量级。为了解释溶液中超高增益系数的根本原因，我们首次表明这些CQW在绿色区域的增益截面≥3.3×10⁻¹⁶ cm²，在红色区域≥1.3×10⁻¹⁶ cm²，与CQD相比大两个数量级。
